Lost connection to ESXi 5.1 host

[Deano123]

I was doing some testing on one of our hosts in preparation for moving from Essentials to Essentials plus when I noticed that most of the vmnic's were only reporting 100MB Full Duplex connection speeds.  We have a Dell R515 with 2 Broadcom NetExtreme II BCM 5709 cards, all set to auto negotiate, so I thought I would try and force one of the vmnics to communicate at 1000Mb Full Duplex.  This has had rather disastrous consequences resulting in lack of connectivity to the host.  In vCentre the host is reported as Disconncted and if I try and connect directly to the host I get a "Cannot connect" type error. 

Fortunately the VM's are still running so I just need to get this host back online.  SSH is off so I can't putty onto the host, though I do have physical access to it if needed. 

The management network is running on vmnic8, which is an on board Broadcom BCM5716, whereas I was editing vmnic6 on one of the Broadcom BCM5709 card, so why I would lose connection o the management network I am a little stumped, any help appreciated.

Cheers

Dean

[a_p_]

I can't tell you why you lost the connection if the vmnics are on two different vSwitches (that's what I understood). However, to bring your host back online, you should be able to login to the DCUI on the host's console to reconfigure the vmnic again. For details see e.g. http://kb.vmware.com/kb/1004089

Regarding the link speed (100MBit/s vs. 1GBit/s), check the physical switch port settings, and also make sure the network cables (as well as any patch connections) the support at least CAT 5e.

André

[Deano123]

Cheers for the reply, you understood correctly.  The vmnics are on different vSwitches and are on different hard ware too.  All ports on the physical switch are set to auto-negotiate and all ports are 10/100/1000.  I hadn't considered the possibility of maybe cat 5 over cat 5e (but I am certain we don't have any cat 5 cable any more), so will check that for completeness.

Will let you know how I get on with the kb article.

Regards
Dean

[a_p_ · Accepted solution]

Just follow the steps in the "Configuring the speed and duplex of the ESXi/ESX host network adapter at the service console" section. In step 1 you'll find the links for how to enable Shell access. Basically you login to the DCUI to enable Shell access in the "Troubleshooting Options" menu, and the press ALT-F1 to switch to the console. After logging in use esxcli network nic list to get an overview of installed vmnics, esxcli network nic get -n vmnic8 to view the settings of vmnic8, and esxcli network nic set -n vmnic8 -a to set speed and duplex to auto. For details about the command see http://pubs.vmware.com/vsphere-50/index.jsp#com.vmware.vcli.ref.doc_50/esxcli_network.html

André

[Deano123]

Nice one, reconnected to vCentre now.  It seems to be that after adding a vmkernel (to be used for iSCSI) port to vSwitch7 (vmnic6) and then trying to change from auto-negotiate to forced connection speeds the system somehow didn't like that configuration and kicked me out. 

Though I did use different commands, esxcfg-nic -l and esxcfg-nic -a vmnic6 to get it back working

Lesson learned

Your help much appreciated

Dean